tcp/udp multicast/broadcast

I'm making a game that requires the connection of two or more players. at the moment if two people are on a LAN or internet they have to specify their addresses explicitly.

I want to know how to broadcast if a player is available on a network, so the user can just click the game name. I thought there where broadcast address for UDP (like 255.255.255.255 or something)

help?

Network IP + append 255.  ie xxx.xxx.xxx.255

>>2
I think that depends on the subnet mask, doesn't it?

>>2
ah, I've done it, thanks alot =D

>>3
it does
read the rfcs or at least wikipedia

>>4
How'd you do it then?

>>6
255.255.255.255

>>7
Because you can broadcast to the entire internet, right? Usually neither multicast nor broadcast packets are routed beyond the local subnet.

>>1
Broadcast and multicast is available at layer 3 (IP) or layer 2 (ethernet or 802.11), not layer 4 (tcp/udp).

BroadcastAddress = (HostIP | (~ SubnetMask));

>>6
A host when searching for a game should broadcast a packet saying 'if you're a game server, please respond'.  Game server on receiving said packet should respond with a packet that contains all details required to establish a connection.  This service requires UDP rather than TCP.  In fact, all gaming should work through UDP, with fault tolerance provided by the application.  Otherwise you get long lags in the event of packet loss, window scaling etc.

>>8
I only wanted it to broadcast to the local network. In order to connect to other players on the internet I'd resolve a dns then connect to that server

UDP is best for FPS and games that require reaction. TCP is best for games like a rts (what I'm developing)

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